Fluid filling apparatus



March 6, 1962 R. c. STRAIN 3,023,791

FLUID FILLING APPARATUS Filed Sept. 4, 1957 IN VEN TOR.

'2 H 5 ROBERT C. STRAIN J BY ATTORNEY United States Patent 3,023,791FLUID FILLING APPARATUS Robert C. Strain, Danville, Ill., assignor toGeneral Electric Company, a corporation of New York Filed Sept. 4, 1957,Ser. No. 681,985 Claims. (Cl. 141270) My invention relates to apparatusfor filling containers with fluid, and more particularly to apparatusfor filling enclosed electrical devices with hardenable liquidinsulating material.

Electrical apparatus such as fluorescent lamp ballasts are often placedin metal containers and embedded in a hardenable liquid insulatingmaterial such as hot sandfilled asphalt by manually pouring the hotasphalt into the container over the ballast components until thecontainer is full. The container is then covered and the asphalt allowedto cool and set. This manual potting operation, as it has become called,has many disadvantages heretofore believed inherent and insurmountable.For example, the asphalt must be kept at a fairly high temperature andcan burn the hands of an operator. It must be poured very rapidly intothe container in order to prevent freezing and resultant voids and yetmust be controlled to fill the container completely so as to producegood thermal contact with the cover. There is, therefore, considerablespilling and spattering of the hot asphalt even in the hands of anexperienced operator. Attempts to prevent spilling by conventionalliquid level controlling apparatus have not been successful since thesurface of the hot asphalt is not level at the time flow must bestopped. In general, this potting operation may be characterized asmessy.

In addition, there is a high rate of ballast spoilage due to voids,especially with shallow ballasts because of insuflicient flow clearancebetween the ballast components and the case. Raising the temperature ofthe asphalt to reduce viscosity and increase flow penetration causesdamage to the electrical connections within the ballast and results inflow of the asphalt out through the lead-accommodating apertures in thecase. Conventional automatic gravity flow filling apparatus are no moreeflective in eliminating these voids than this manually controlledpotting operation, while conventional pressure rlling apparatus are notsuitable since they result in the extrusion of the hot asphalt throughthe lead accommodating apertures and through the filling aperture.

Accordingly, an important object of my invention is to provide apparatusfor automatically and mechanically performing this potting operation.

Another object of the invention is to provide apparatus for embedding anelectrical device in hardenable liquid insulating material within anenclosing case in a manner completely filling the case without voids andwithout appreciable overflow even when there is only slight clearancebetween the components of the enclosed device or between thesecomponents and the enclosing case.

In general, in accord with the invention, pressure filling apparatus isprovided having means responsive to the movement of a fluid ejector fordeveloping an increasing pressure to counteract the fluid ejectingpressure so that these two pressures approach but do not reachequilibrium as a container enclosing an electrical device is filled bythis apparatus. The nozzle of the fluid ejector is located within afilling aperture in the container such that a continuous confined streamof fluid is produced when the fluid reaches the top thereby to generatean additional impedance or load upon the fluid ejector and immediatelystop fluid flow before a build up of back pressure suiflcient to extrudefluid from any openings can occur. In this way, the fluid is firstdriven into the interstices of the enclosed electrical device at highspeed and under high pressure until the container is almost completelyfilled, whereupon the speed and pressure of fluid flow gradually reducesand stops automatically as soon as the container is saturated. Inaddition, the greater speed of fluid injection resulting from thisapparatus permits the use of a fluid consisting of a hardenable liquidinsulating material having a considerably lower temperature than thatpermissible with gravity flow, whereby there is less shrinkage andpossibility of voids during cooling and the viscosity of the liquid isgreater, resulting in a lesser degree of extrusion through vents, suchas lead-accommodating holes and other small openings at the joints ofthe case.

In accord with further features of the invention, means are provided forapplying and removing the driving and counteracting pressuresautomatically in sequence, and for making this sequence responsive tothe presentation and removal of a container to and from the nozzlewhereby a succession of containers may be filled automatically. Aspecial nozzle movable between open and closed positions is provided forthis purpose.

The novel features believed to be characteristic of the invention areset forth in the appended claims. The invention itself together withfurther objects and advantages thereof can be easily understood byreferring to the following description taken in connection with theaccompanying drawing in which,

FIGURE 1 is a schematic diagram of a fluid filling apparatus embodyingthe invention; and

FIGURE 2 is a sectional view of a nozzle preferably employed in theapparatus of FIGURE 1.

Referring to FIGURE 1, one form of the invention is shown as comprisinga nozzle assembly 1&5, and means for ejecting fluid from said nozzleassembly including a fluid ejector 11 and a fluid pump 12 preferablypneumatic, as shown. A fluorescent lamp ballast 13 having an enclosingcase or container 14 is shown in position to be filled by fluid ejectedfrom nozzle ltl. Ballast 13 is presented for filling after it has beencompletely manufactured except for this final potting operation. Coverplate 15, having a fluid receiving aperture 16 therein, is alreadyfastened to the body of the case 14 and leads 17 extend throughlead-accommodating apertures 18 in the ends of this case 14. Ballast 13is supported on a movable carrier 19 which may be raised or lowered asindicated by arrow 20 to bring successive ballasts 13 into and out ofengagement with the lower end of nozzle assembly 1t).

Nozzle assembly 10, best seen in FIGURE 2, comprises a base 21 and ahead assembly 22 connected together by a bellows 23 surrounded by ametal jacket 29, a heating tube 29a, and a compression spring 24. Headassembly 22 has a central conical bore 25 opening into an outlet orificeor nozzle 26 surrounded by a gasket 22a. This orifice is normallycovered by a plug 27 carried by an axial rod 28 attached to base 21.When head assem- J bly 22 is elevated against the force of spring 24,however, the end of head assembly 22 is moved away from plug 27 and theoutlet orifice 26 is opened.

Fluid ejector 11 is connected through check valve 39 and conduit 31 todeliver fluid into nozzle assembly 1%), and is connected through anothercheck valve 32 and conduit 33 to receive fluid in the form of hotasphalt 34 from a tank or other source of supply 35. Fluid ejector 11comprises a fluid chamber 36 which may be T-shaped "as shown, having apiston 37 reciprocable within one cylindrical open end of chamber 36.Reciprocation of piston 37 in one direction as indicated by arrow 38produces suction within fluid chamber 36 which causes the injection orintake of hot asphalt 34 into chamber 36 through inlet check valve 32from tank 35 while closing outlet check valve 30. Reciprocation ofpiston 37 in an opposite direction, indicated by arrow 39, produces afluid pressure Within chamber 36 closing inlet checkvalve 32 and drivingany hot asphalt within fluid chamber 36 through outlet check valve 30and conduit 31 into nozzle assembly 10.

Pneumatic pump 12 is mechanically connected to connecting rod 40 tocontrol the operation of piston 37. Pump 12 comprises a cylindrical gaschamber 41 containing a piston 42 reciprocable within and "against thewalls of chamber 41, piston 42 being attached to connecting rod 40. Gaschamber 41 has its opposite ends closed by end walls 43 and 44 wherebythe chamber 41 is divided 7 by piston 42 into two pressure chambers 45and 46' respectively. Connecting rod 40 is reciprocable through end wall44 by means of a substantially fluid tight seal (not shown). Fluidconduits 47 and 48 open through end walls 43 and 44 into these pressurechambers 45 and 46 respectively. Piston 42 is, of course, movable inresponse to the difference in gas pressure within chambers 45 and 46.

A first gas or other fluid pressure for driving pistons 42 and 37 in anasphalt ejecting direction 39 of fluid ejector 11 is arranged to bedelivered into pressure chamber 45 from. a suitable source of air orother gas or fluid pressure through a first regulating valve 50 and afirst solenoid controlled valve 51 connected in series with one anotherin. conduit 47. Gas pressure for counteracting this driving pressure andfor moving pistons 42 and 37 inan asphalt intake direction 38 issupplied to pressure chamber 46 through a second flow regulating valve52 and a second solenoid actuated valve 53 in series with one another inconduit 48. Regulating valves 50 and 52 are adjusted so that the drivingpressure delivered to chamber 45 is substantially greater than thecounteracting fluid pressure delivered to chamber 46 of pump 12.

Solenoid valve 51 is controlled by its solenoid 55 to open when thesolenoid 55 is energized and to close and vent on its outlet side whenthe solenoid 55 is de-energized. Solenoid valve 53, however, is of thetype having one solenoid 56 which opens valve 53 when energized and asecond solenoid 57 which closes and vents valve 53 on the outlet sidewhen this second solenoid 57 is energized. Solenoids 55, 56 and 57 arerespectively electrically connected to be energized by three limitswitches 58, 59 and 60. As can be seen from the circuit connections ofFIG- URE 1, limit switch 58 is connected in series with solenoid 55across a source S of suitable voltage; limit switch 59 is connected inseries with solenoid 56 across electric voltage source S; while limitswitch 6% is connected in series with solenoid 57 across source S. Limitswitch 58 is located to be actuated when the orifice 26 of nozzle isopened by the elevation of head assembly 22. Limit switch S8 is thusresponsive to the presentation and removal of a ballast 13 to and fromthe nozzle. Limit switches 59 and 6% are arranged on opposite sides of ablade 62 rigidly fastened to connecting rod 40. Limit switch 59 isarranged to be actuated by blade 62 near the end of the driving strokeof piston 42 while limit switch 69 is arranged to be actuated by blade62 near the end of its return stroke. The position of switch 59 relativeto that of blade 62 is preferably made adjustable for a purpose to beexplained. It will thus be seen that the operation of limit switches 59and 60 and their associated solenoids 56 and 57 are responsive topredetermined positions in the cyclical movement of piston 42.

in the operation of the pressure filling apparatus of FIGURE 1, presumepiston 42 of pneumatic pump 12 at the left hand end of its cylinder 41and presume no ballast under nozzle assembly 10. Under these conditionsfluid ejector chamber 36 will be filled with hot asphalt but no asphaltwill flow from nozzle assembly 10 since the nozzle 26 will be closed asthe head assembly 22 is depressed against plug 27 by compression spring24. Limit switch 58 will be open whereby solenoid 55 is de-energized andvalve 51 is closed and vented. Limit switch 59 will be open and limitswitch 60 will be closed whereby solenoid 56 will be de-energized andsolenoid 57 energized to close and vent valve 53. When a ballast 13 isplaced. on carrier 19 and elevated, the ballast first engages gasket 22aof nozzle head assembly 22 with its filling aperture 16 registering withthe outlet nozzle or orifice 26, and upon continued elevation, nozzlehead assembly 22 is retracted away from plug 27 both to open orifice 26and close limit switch 58. The closure of limit switch 58 energizessolenoid 55 and opens valve 51 to admit regulated driving gas pressureinto pressure chamber of pump 12. Since pressure chamber 46 is ventedthrough valve 53, the piston 42 is driven rapidly toward the right handend of pump 12 under the influence of this driving gas pressure. Piston37 of fluid ejector 11 is correspondingly driven at a high rate of speedto eject the hot liquid asphalt 34 through check valve 30 and nozzleassembly 10 into ballast '13. This high pressure injection of fluid intothe ballast container continues during the major portion of the pistonstroke until the ballast is almost full whereupon blade 62 engages theoperating arm of limit switch 59. The closure of limit switch 59completes the circuit to energize solenoid 56 and open valve 53whereupon a counteracting gas pressure is supplied into chamber 46 ofpump 12 through regulating valve 52 and conduit 48. This counteractinggas pressure automatically increases as piston 42 continues to driveforward under the influence of inertia and of the 5 driving gas pressurein chamber 45 and is adjusted by means of regulating valve 52 toapproach but not quite reach equilibrium at the time the ballastcontainer 14 becomes completely full. It will be appreciated that thepoint of introduction of this counteracting gas pressure during thedriving stroke can be adjusted by varying the position of limit switch59 relative to that of actuating blade 62. Once the ballast 13 becomescompletely full, the increased load upon the fluid ejector 11 resultingfrom the increased impedance upon and confinement of the fluid streamhas been found to be sufficient to stop completely the movement ofpiston 42 and thereby to stop the further flow of fluid from nozzleassembly 10.

Carrier 20 is then lowered permitting nozzle head assembly 22 to movedownward first to open limit switch 58, and subsequently to close thenozzle or orifice 26 as the ballast moves out of engagement with thehead 22. When limit switch 58 opens, solenoid is de-energized therebyclosing and venting valve 51 so that piston 42 is driven to the left ona return stroke under the influence of the gas pressure still existingin gas chamber 46. During this return stroke, piston 37 of fluid ejector11 injects a fresh supply of hot asphalt into the fluid ejector 11.Also, during this return stroke, limit switch 59 is opened and limitswitch is closed by the leftward movement of actuating blade 62. Theclosure of limit switch 6%} at the end of the return stroke energizessolenoid 57 to close and vent valve 53 and prepare the pump for the nextoperation. A succession of ballasts may thus be filled automatically bymerely presenting and removing them in succession to and from nozzleassembly by means of carrier 19. It will be appreciated that because ofthe high pressure injection of the hot asphalt into the ballast duringthe initial portion of the driving stroke, the possibility of voids isvirtually eliminated and relatively low temperature asphalt of highviscosity may be used.

As an example of my invention, ballasts having a flow clearance betweenenclosed electrical device and case of less than 3' inch have beensuccessfully filled by the above described apparatus using an asphaltfilled with 53% silica maintained at a temperature of approximately 180C. and using a driving air pressure regulated by valve 50 at 95 lbs/sq.inch and a counteracting air pressure regulated by valve 53 at 60lbs/sq. inch introduced after the ballast was filled 90% of its completecharge.

Although I have described my invention in connection with hot asphalt,other fluids, especially liquids whose viscosity decreases withtemperature increases, may be employed. It will also be appreciated thatalthough I have shown only one embodiment of my invention, manymodifications may be made, and I intend by the appended claims to coverall such modifications as fall within the true spirit and scope of theinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for fluid filling of containers comprising a nozzle, meansmovable in response to a first driving pressure for initially ejectingfluid from said nozzle at a first rate of flow, means responsive to themovement of said ejecting means for generating an increasingcounteracting pressure on said ejecting means to reduce gradually therate of flow from said nozzle, said driving and counteracting pressuresapproaching equilibrium after a predetermined volume of fluid flow, andmeans for additionally appyling to said ejecting means the back pressuregenerated by impedance in the flow of fluid ejected by said nozzle,thereby to terminate the movement of said ejecting means and stop theflow of fluid into the container being filled.

2. For use with a substantially closed container to be filled, saidcontainer having a filling aperture and being vented, fluid fillingapparatus comprising a nozzle fitting snugly within said fillingaperture, means movable in response to a first driving pressure forinitially ejecting fluid from said nozzle at a first rate of flow, meansresponsive to the movement of said ejecting means for generating anincreasing counteracting pressure on said ejecting means to reducegradually the rate of flow from said nozzle and means for additionallyapplying to said ejecting means the fluid pressure built-up within saidcontainer thereby to arrest the movement of said ejecting means and stopthe flow of fluid from said nozzle.

3. Apparatus for fluid filling of containers comprising a nozzle,pneumatic means including a reciprocable piston, means connected to saidpiston for ejecting fluid from said nozzle at a rate of flow dependentupon the speed of motion of said piston during its stroke in onedirection, means for introducing a driving air pressure on one side ofsaid piston to initiate a stroke of said piston in said one direction,means responsive to the motion of said piston during said stroke forintroducing a counteracting air pressure on the other side of saidpiston, said counteracting air pressure increasing as said strokecontinues to reduce gradually the speed of motion of said piston towardthe end of said stroke.

4. Apparatus for fluid filling of containers comprising a movablenozzle, means movable in response to fluid pressure for ejecting fluidfrom said nozzle, means responsive to the movement of said nozzle fordelivering a first driving fluid pressure to said fluid ejecting means,and means responsive to the movement of said ejecting meansautomatically introducing a second fluid pressure to said ejecting meanscounteracting said first fluid pressure to reduce gradually the rate offlow of fluid ejected from said nozzle.

5. Apparatus for fluid filling of containers comprising a nozzle, meansmovable in response to a first driving fluid pressure for ejecting fluidfrom said nozzle, a limit switch arranged to be operated by said fluidejecting means during its movement, means including a solenoid valveenergized by the operation of said limit switch for delivering a secondfluid pressure into said fluid ejecting means in a directioncounteracting said driving fluid pressure to gradually reduce themovement of said fluid ejecting means and the ejection of fluid fromsaid nozzle.

6. Apparatus for fluid filling of enclosed electrical devices comprisinga nozzle, a fiuid chamber connected to said nozzle and having a firstreciprocable piston for ejecting fluid from said nozzle, a gas chamberhaving a second reciprocable mechanical piston mechanically connected tosaid first piston, means for delivering gas under a first pressure intosaid gas chamber on one side of said second piston to initiate a strokeof said first piston, a limit switch arranged to be operated by saidpistons during said stroke, and means including a solenoid valveenergized by the operation of said limit switch for delivering gas undera second gas pressure into said gas chamber on the other side of saidsecond piston at a pressure less than said first pressure, said secondpressure increasing as said stroke progresses and functioning togetherwith the fluid load on said first piston to arrest said stroke of saidpistons.

7. Apparatus for fluid filling of containers comprising a nozzle movablebetween open and closed positions, a fluid chamber opening into saidnozzle and having a first reciprocable piston for injecting fluid intosaid chamber upon movement in one direction and for ejecting fluid outof said chamber into said nozzle during movement in an oppositedirection, and means including a pneumatic pump for reciprocating saidpiston in response to the movement of said nozzle between its open andclosed positions, said last mentioned means moving said piston a singlestroke in said one direction in response to the movement of said nozzleto said closed position, and moving said piston a single stroke in saidopposite direction in response to the movement of said nozzle to saidopen position.

8. Apparatus for fluid filling of containers comprising a nozzle movablebetween open and closed position, a fluid chamber opening into saidnozzle and having a reciprocable piston for injecting fluid into saidchamber upon movement in one direction and for ejecting fluid out ofsaid chamber into said nozzle during movement in an opposite direction,a pneumatic pump connected to operate said piston, solenoid valve meansfor controlling the operation of said pneumatic pump, and limit switchmeans responsive to the movement of said nozzle for energizing andde-energizing said solenoid valve means.

9. Apparatus for fluid filling of containers comprising a nozzle movablebetween open and closed positions, a fluid chamber opening into saidnozzle and having a first reciprocable piston for ejecting fiuid out ofsaid chamber into said nozzle upon movement in one direction and forinjecting into said chamber upon movement in an opposite direction, agas chamber having a second reciprocable piston mechanically connectedto said first piston, means for delivering gas under a first pressureinto said gas chamber on one side of said second piston to drive saidfirst piston in said one direction, means for delivering gas under asecond pressure into said gas chamber on the other side of said pistonduring its movement in said one direction, and means responsive to theclosing movement of said nozzle for venting said gas chamber on said oneside of said second piston.

10. Apparatus for fluid filling of containers comprising a nozzlemovable between open and closed positions, a fluid chamber opening intosaid nozzle and having a first reciprocable piston for ejecting fluidout of said chamber into said nozzle upon movement in one direction andfor injecting fluid into said chamber upon movement in an '5 oppositedirection, a gas chamber having a second reciprocable pistonmechanically connected to said first piston, means responsive to theopening movement of said nozzle for delivering gas under a firstpressure intosaid gas chamber on one side of said second piston to drivesaid first piston in said one direction, means responsive to themovement of said pistons during its stroke in said one direction fordelivering gas under a. second pressure less than said first pressureinto said gas chamber on the other side of said second piston, and meansresponsive to a closing movement of said nozzle for vent- ReferencesCited in the file of this patent UNITED STATES PATENTS 1,586,770 Badouxet a1 June 1, 1926 2,096,499 Mandell Oct. 19, 1937 2,613,023 Reich Oct.7, 1952 2,661,885 McBean Dec. 8, 1953 2,689,075 Morton et a1 Sept. 14,1954

